Recording medium, recording device, program, and recording method

ABSTRACT

A BD-ROM on which a VC-1 video stream and an entry map (EP_map) are recorded. The VC-1 video stream includes: (a) picture data (I/P picture) whose first fields are the intra frame coding format and whose second fields are the inter frame predictive coding format; and (b) picture data (P/I picture) whose first fields are the inter frame predictive coding format and whose second fields are the intra frame coding format. The entry map indicates entry positions (SPN) of the I/P pictures, in correspondence with playback times (PTS), but does not indicate entry positions of the P/I pictures.

TECHNICAL FIELD

The present invention belongs to a technical field including a randomaccess technology.

BACKGROUND ART

The random access technology is a technology for converting a givenpoint on a time axis of a video stream into a recording position in thevideo stream, and enabling a playback of the video stream to be startedfrom the recording position. The random access technology is a basictechnology that is indispensably required for playing back a videostream recording on a recording medium such as BD-ROM or DVD-Video.

When the video stream is composed of picture data encoded by avariable-length encoding method, the amount of information per picturevaries. As a result, “stream analysis” is required to achieve the randomaccess to the video stream. Here, the “stream analysis” is a process inwhich a process of extracting a header of a picture from the streambody, reading the picture size from the header, and identifying therecording position of the next picture from the picture size is repeateda plurality of times until the recording position of a desired pictureis identified. Such an analysis requires highly frequent accesses to thestream. As a result, it takes a considerable time before a random accessis completed. For this reason, an entry map is required whenabove-mentioned conversion is executed for a random access. Here, theentry map is information that indicates a plurality of entry times onthe time axis in correspondence with a plurality of entry positions inthe video stream. With use of the entry map, for example, when theplurality of entry times in the entry map have a time accuracy of onesecond, it is possible to perform the random access with a highefficiency, namely, at the time accuracy of one second.

In a random access to a video stream, it is required to search for apicture that is present at the start of a GOP. A data structure forsupporting the search of the starting picture of a GOP has been providedas prior art in the following document.

-   Document 1: Japanese Patent Application Publication No. 2000-228656

DISCLOSURE OF THE INVENTION The Problems the Invention is Going to Solve

Some encoding methods of video streams, however, produce such videostreams that have a small amount of pictures whose fields all conform tointra frame coding format. When any conventional entry map is set insuch a video stream, the entry map cannot have sufficient number ofentry positions, and the intervals between continuous entry positionsare extended. When the intervals between continuous entry positions areextended, the references to the entry map become less sufficient, and alarger number of analyses of the stream are required. This lengthens aresponse time, namely a time period from an issuance of the accessinstruction by the user to the actual reading of the stream portion atthe specified position, since, as described above, the analysis of astream requires highly frequent accesses to the stream.

On the other hand, if the starting picture data of the access unit ofthe video stream is specified as an entry position, it may be possibleto select, as an entry position, picture data in which only part of theplurality of fields, which constitute one picture, conforms to the intraframe coding format. In this case, the proper decoding of the picturedata, which is selected in the above-described manner, is notguaranteed. As a result, when a random access is started from an accessunit that starts with such picture data, a playback is performed whilesome of the fields are missing. When this happens, the image isdisplayed at a half degree of resolution.

That the resolution changes between the full and half degrees dependingon the access position is an unstable factor for the quality. This is aserious problem in the home electric appliance industry who are quitenervous about the image quality. As a result of this, playbackapparatuses, which are used to play back the above-described videostreams, hardly become prevalent in the market.

It is an object of the present invention to provide a recording mediumthat can remove the unstable factor in the aspect of quality that theresolution changes between the full and half degrees depending on theaccess position in a random access.

Means to Solve the Problems

An encoding format, which has a small amount of pictures whose fieldsall conform to intra frame coding format, is called “VC-1”.

In “VC-1”, the encoding format can be changed for each field. As aresult, P/I picture, which is picture data composed of a first fieldbeing the inter frame predictive coding (Predictive) format and a secondfield being the intra frame coding (Intra) format, may become thestarting picture of a GOP. If such pictures have been positivelyincluded in the entry map as entry positions, when a playback is startedat a picture having a field of such format, some of the fieldsconstituting the picture may not be decoded. When some fields are notdecoded, the image is displayed with a half degree of resolution.

The above object is fulfilled by a recording medium on which a videostream and an entry map are recorded, wherein the entry map includes aplurality of pieces of entry information, each piece of entryinformation indicates an address of picture data, and the entry map doesnot include entry information that indicates an address of picture datawhose first fields are an inter frame predictive coding format and whosesecond fields are an intra frame coding format.

Effects of the Invention

With the above-described structure of the recording medium in which theentry map does not include such entry information that indicates anaddress of picture data whose first fields cannot be decoded, it ispossible to execute a random access by preventing images from beingdisplayed with a half degree of resolution.

As far as random accesses are performed using the entry map having theabove-described structure, the resolution of images does not changebetween the full and half degrees depending on the access position inthe random accesses during a playback by a playback apparatus.

In so far as the entry map in the recording medium is used, theresolution of images does not change between the full and half degrees.This eliminates an unstable factor for the quality, and the homeelectric appliance industry can bring playback apparatuses for playingback VC-1 video streams, into the market without worry. This opens theway for the prevalence of such playback apparatuses.

In terms of reducing the response period, it is desirable that the entrymap includes entry information that indicates an address of picture datawhose first fields are the intra frame coding format and whose secondfields are the inter frame predictive coding format.

With this structure, GOPs that start with a picture whose first fieldsare the intra frame coding (Intra) format are specified as entrypositions, even if the second fields are the inter frame predictivecoding (Predictive) format.

When the decoding starts with an I/P picture that is composed of firstfields of the Intra format and second fields of the Predictive format,both the first fields and the second fields are decoded appropriately.This is not achieved when the decoding starts with a P/I picture. Thisis because in most cases, the second fields of the Predictive formatrefer to the first fields of the Intra format.

With the above-described structure, not only GOPs that start with theI/I picture whose first field and second field are both the Intraformat, but also GOPs that start with the I/P picture are specified asentry positions. As a result of this, the time intervals between entrytimes become shorter. Due to this, sections in the stream that aresubjected to the stream analysis are also shortened. This reduces aresponse time, namely a time period from issuance of a random accessinstruction by the user to the actual reading of the stream portion atthe specified position.

The above-stated recording medium may further record a status flagtherein, where the status flag indicates that the entry map does notinclude entry information that indicates an address of picture datawhose first fields are the inter frame predictive coding format andwhose second fields are the intra frame coding format.

With the above-described structure, it is possible to convey to aplayback apparatus that the video stream includes other access unitsthat are not specified by the entry information. The entry informationregarding the P/I picture is omitted, and the interval between the entrypositions has been extended as much as the omitted information. Theplayback apparatus can judge whether or not to supplement the extendedinterval by the stream analysis. Playback apparatuses having relativelyhigh stream analysis ability can judge to supplement the extendedinterval by the stream analysis, and playback apparatuses havingrelatively low stream analysis ability can adopt an alternative methodof restricting access destinations of the random accesses.

The above-described structure makes it possible to select either thestream analysis or restriction of access destinations of the randomaccesses, as a method of supplementing the extended interval between theentry positions. This prevents the user response from being degradedremarkably during execution of a random access by the playbackapparatus.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a recording apparatus and a recording medium of the presentinvention and a playback apparatus.

FIG. 2A shows a VC-1 video stream.

FIG. 2B shows a sequence of sets of pieces of picture data that belongto GOP #1, #2, #3, . . . #7, respectively.

FIG. 2C shows the field structure of the video stream shown in FIG. 2B.

FIG. 3A shows the structure of the P/I picture.

FIG. 3B shows the structure of the I/P picture.

FIG. 4A shows a jump-in playback in a video stream encoded by VC-1.

FIG. 4B shows how decoding is performed when the playback is startedfrom a P/I picture that is the starting picture of the GOP.

FIG. 5A shows the field structure of GOPs in the video stream in thesame manner as in FIG. 2B.

FIG. 5B shows first fields in the Predictive format that cannot bedecoded in the double speed playback.

FIG. 6 shows an internal structure of the recording apparatus in thepresent embodiment.

FIG. 7A shows an EP_map generated when an EP_map is not present in theinput video stream.

FIG. 7B shows an EP_map that is generated by the EP_map generating unit5 when an input TS includes a P/I picture.

FIG. 8 is a flowchart showing the procedures in which the EP_mapgenerating unit 5 generates the EP_map.

FIG. 9 shows the EP_map generated for the AVClip shown in FIG. 2.

FIG. 10 shows the playback process performed by the playback apparatusin which the EP_map is referred to.

FIG. 11 shows an internal structure of the recording apparatus inEmbodiment 2.

FIG. 12A shows an EP_map that is provided with a type flag.

FIG. 12B shows the meaning of the type flag.

FIG. 13 is a flowchart showing the procedures of the EP_map generatingunit 5 in Embodiment 2.

FIG. 14 shows the EP_map generated for the AVClip shown in FIG. 2.

FIG. 15 shows the internal structure of the Clip information.

FIG. 16 shows the EP_map setting for the video stream.

FIG. 17 shows the PTS_EP_start and the SPN_EP_start of Entry Point #1 toEntry Point #5 shown in FIG. 16, by pairs of EP_Low and EP_High.

DESCRIPTION OF CHARACTERS

-   1 ATS attaching unit-   2 stream analyzing unit-   3 FIFO memory-   4 memory-   5 EP_map generating unit-   6 drive-   100 recording apparatus-   200 recording medium-   300 playback apparatus

BEST MODE FOR CARRYING OUT THE INVENTION

The following describes embodiments of the recording medium and therecording apparatus of the present invention, with reference to theattached drawings. FIG. 1 shows a recording apparatus and a recordingmedium of the present invention and a playback apparatus.

<Recording Apparatus 100>

A recording apparatus 100 receives an input video stream in a transportstream (TS) format via an interface such as IEEE1394, subjects it to avideo stream format conversion, and writes the result of the conversiononto a recording medium 200. In this conversion, a video stream in theTS format is converted into an AVClip format conforming to a BD-ROMstandard. The input video streams include VC-1 video streams, MPEG4-AVCvideo streams, and MPEG2-Video video streams. FIG. 2A shows a VC-1 videostream. The VC-1 is an encoding method made by SMPTE (The Society ofMotion Picture and Television Engineers). The VC-1 is based on theMPEG2-Video method or the MPEG4-Visual method, and has been extendedwith an encoding tool and the like.

In the VC-1, three profiles (simple, main, and advanced) are defined.The advanced profiles have a GOP (Group Of Pictures) structure that isalso defined in the MPEG-2 Video.

The VC-1 video stream includes a plurality of video access units (VideoAccess Unit #1, #2, #3, . . . #7). These video access units constitutewhat is called GOP. Each video access unit is composed of:SeQuence_Header (SQH) that indicates the start of a GOP; and a pluralityof pieces of picture data. These GOPs are classified into three types:(i) GOPs whose starting picture is I/I picture; (ii) GOPs whose startingpicture is I/P picture; and (iii) GOPs whose starting picture is P/Ipicture. It is presumed here that Video Access Unit #1, #2, #3, . . . #7shown in FIG. 2A correspond to GOP #1, #2, #3, . . . #7, respectively.

FIG. 2B shows a sequence of sets of pieces of picture data that belongto GOP #1, #2, #3, . . . #7, respectively. In FIG. 2B, it is presumedthat the starting picture of GOP #1 is I/I picture, the starting pictureof GOP #4 is I/P picture, and the starting pictures of GOPs #2, #3, #5,and #6 are P/I pictures.

FIG. 2C shows the field structure of the video stream shown in FIG. 2B.FIG. 3A shows the structure of the P/I picture. As shown in FIG. 3A, theP/I picture is composed of first fields being the inter frame predictive(Predictive) coding format and second fields being the intra framecoding (Intra) format. Since the first fields are the Predictive format,the P/I picture is required to refer to a picture which belongs to apreceding GOP.

FIG. 3B shows the structure of the I/P picture. As shown in FIG. 3A, theI/P picture is composed of first fields being the intra frame coding(Intra) format and second fields being the inter frame predictive coding(Predictive) format. Although the second fields are the Predictiveformat, they generally refer to the first fields in the same picturedata. Up to now, the internal structure of the video stream has beendescribed.

<Recording Medium 200>

The recording medium 200 is a recording medium in which AVClips arestored in correspondence with EP_maps.

<Playback Apparatus 300>

A playback apparatus 300 plays back AVClips stored in the recordingmedium 200. The playback available by the playback apparatus 300 isclassified into a normal playback, a jump-in playback, and adouble-speed playback. Of these, the double-speed playback is oneapplication of the random access.

FIG. 4A shows a jump-in playback in a video stream encoded by VC-1. Inexecuting the jump-in playback, the playback apparatus 300 receives,from the user, input of a chapter number and input of a time specifyingthat “the playback be started from xx(hours):yy(minutes):zz(seconds)”,determines a playback time point from which the playback should bestarted, detects a GOP that is closest to the determined playback timepoint, reads the detected GOP and the succeeding GOPs from the AVClip,and provides the decoder with the read GOPs.

The video stream shown in FIG. 4A is the same as the video stream shownin FIG. 2A. It is supposed here that the user instructed to perform ajump-in playback in a GOP whose starting picture is a P/I picture. Thefirst field of the P/I picture is the Predictive format, thus it refersto any picture in the preceding GOP, as indicated by the arrow in thedrawing. FIG. 4B shows how decoding is performed when the playback isstarted from a P/I picture that is the starting picture of the GOP. InFIG. 4B, the sign “×” indicates that the first fields attached with thesign “×” cannot be decoded since the reference image is not present inthe decoder. When this happens, the first fields cannot be decoded untila first field in the Intra format is read out by the playback apparatus300. This reduces the resolution to half.

FIG. 5A shows accesses to a video stream in the double speed playback.In FIG. 5A, the field structure of GOPs in the video stream isrepresented in the same manner as in FIG. 2B. The first row in thedrawing shows accesses to GOPs in the double speed playback. As shown inthe first row of the drawing, the double speed playback is achieved byrepeating a process in which only the starting picture of a GOP is readout, and the reading position moves to the picture of the next GOP.

FIG. 5B shows first fields that cannot be decoded in the double speedplayback. In FIG. 5B, the sign “x” indicates that the first fieldsattached with the sign “x” cannot be decoded. This is because all thesefirst fields are the Predictive format. The first fields cannot bedecoded in the sections in which the Predictive format is present inthis manner, and the resolution becomes half.

The recording apparatus 100 in the present embodiment is structured toavoid the resolution from becoming half during the jump-in playback orthe double-speed playback, as shown in FIG. 6. FIG. 6 shows an internalstructure of the recording apparatus 100 in the present embodiment. Asshown in FIG. 6, the recording apparatus 100 includes an ATS attachingunit 1, a stream analyzing unit 2, a FIFO memory 3, a memory 4, anEP_map generating unit 5, and a drive 6.

The ATS attaching unit 1 detects isochronous packets that are insertedin a TS packet at various locations, and generates Arribal_Time_Stampsbased on the times that the clock of the recording apparatus measures atpoints in time when the isochronous packets are detected. The ATSattaching unit 1 then attaches the Arribal_Time_Stamps to the TS packet.The Arribal_Time_Stamps are used to refer to time stamps such as PCR andPTS during a stream playback. In general, PCR and PTS are set in a videostream of the MPEG2-TS format transmitted from a broadcast station onthe presumption that it is received and played back in real time. Duringan accumulation playback, however, a video stream of the MPEG2-TS formatis accumulated in a recording medium first, and then is played backafter a considerable time period lapses. In such an accumulationplayback, the values of PCR and PTS, which are adjusted for the purposeof playing back in real time, are wasted. As a result, theArribal_Time_Stamp in the TP_extra_header indicates a time at which theTS packet arrives the recording apparatus. Accordingly, with anarrangement in which this Arribal_Time_Stamp is referred to during theplayback, the playback timing control using the PTS and PCR is availableas in a playback in real time even if a video stream of the MPEG2-TSformat is first accumulated in a Blu-ray disc or the like, and thenplayed back. Each TS packet has 188 bytes, and each TS_extra_header hasfour bytes. Accordingly, the TS packet attached with the TS_extra_headeras described above has 192 bytes.

The stream analyzing unit 2 determines the encoding method of a videostream when it is input into the recording apparatus 100, judges whetheror not the SQH is present in a TS packet, for each of TS packets thatare sequentially input, and if the SQH is present, detects PTS(Presentation Time Stamp) and SPN (Source Packet Number) from thepicture (namely, the starting picture of the GOP) that succeedsimmediately to the SQH. Here, the PTS is a time stamp that defines theplayback start time of a picture, and the SPN indicates a packet numberof a TS packet that stores the starting portion of the picture. Thestream analyzing unit 2 also determines the picture type of the picture.

The FIFO memory 3 is achieved by a FIFO for storing TS packets attachedwith TS_extra_headers (hereinafter merely referred to as EXs) by thefirst-in-first-out method. A group of 32 pieces of TS packets with EXshas 6144 (=32×192) bytes. This size matches the size of three sectors(6144=2048×3). The 32 pieces of TS packets with EXs stored in threesectors are called “Aligned Unit”.

The memory 4 is a memory for storing EP_maps. The data indicating thenavigation structure of the recording medium 200 is stored in the memory4 until the entire stream has been recorded, and the data indicating thenavigation structure of the recording medium 200 is written on therecording medium after the recording of the entire stream is completed.

The EP_map generating unit 5 generates an EP_map on the memory 4 usingthe PTS and SPN sent from the stream analyzing unit 2. The EP_mapgenerated by the EP_map generating unit 5 has a different formatdepending on whether the P/I picture is present. FIG. 7A shows an EP_mapgenerated by the EP_map generating unit 5 when the P/I picture ispresent in the input video stream. The EP_map shown in FIG. 7A includesgeneral information thereof (EP_map_GI) and an entry group. The entrygroup is composed of a plurality of pieces of entry information. Theentry information indicates an entry time and an entry position incorrespondence with each other. Here, the entry time is represented by aPTS of an I/I picture or an I/P picture, and the entry position isrepresented by an SPN of an I/I picture or an I/P picture.

The EP_map_GI includes a status flag. The status flag is a flagindicating the status of an EP_map. When the status flag is set to “1”,it indicates that the P/I picture is present in the stream, but that theEP_map does not specify the P/I picture.

When the status flag is “0”, the playback apparatus recognizes that theP/I picture is not present in the video stream, and that the intervalbetween the entry positions has minimum narrowness. On the other hand,when the status flag is “1”, the playback apparatus recognizes that thevideo stream includes P/I pictures that are not specified as entrypositions and thus are omitted, and that the interval between the entrypositions has been extended as much as the omitted P/I pictures. Theplayback apparatus can judge, by referring to the status flag, whetheror not to supplement the extended interval by the stream analysis.Playback apparatuses having relatively high stream analysis ability canjudge to supplement the extended interval by the stream analysis, andplayback apparatuses having relatively low stream analysis ability canadopt an alternative method of restricting access destinations of therandom accesses.

The above-described structure makes it possible to select between thestream analysis and the restriction of the access destinations tosupplement the extended interval between entry positions, thuspreventing the user response from being degraded remarkably duringexecution of a random access by the playback apparatus.

The drive 6 attaches error correction codes to a plurality of AlignedUnits stored in the FIFO memory 3, and write them onto the recordingmedium 200. This writing process is continued as far as TSs are input tothe recording apparatus 100 in sequence and Aligned Units are newlystored in the FIFO memory 3. When the input of TSs stops and generationof new Aligned Units is ended, the EP_map that is present in the memory4 is written onto the recording medium 200.

Up to now, the internal structure of the recording apparatus in thepresent embodiment has been described.

The playback apparatus 300 can recognize, by referring to the statusflag in the EP_map_Gi of the EP_map, whether an AVClip to be played backdoes not include a P/I picture, or the AVClip to be played back includesa P/I picture but the EP_map does not specify the P/I picture.

FIG. 7B shows an EP_map that is generated by the EP_map generating unit5 when an input TS does not include a P/I picture. In FIG. 7B, the entrygroup indicates addresses of I/I pictures or I/P pictures incorrespondence with PTSs. On the other hand, the status flag included inthe EP_map_GI of this EP_map is set to “0”. The value “0” set in thestatus flag indicates that the input TS does not include a P/I picture.The playback apparatus can recognize, by referring to this value of thestatus flag, that the AVClip to be played back does not include a P/Ipicture.

FIG. 8 is a flowchart showing the procedures in which the EP_mapgenerating unit 5 generates the EP_map. In step S1 of this flowchart,the status flag is set to indicate that the P/I picture is present inthe stream, then a loop process composed of steps S2-S3 is performed.The steps S2-S3 are performed to monitor the input of TS packets to theapparatus. In step S2, it is judged whether or not an input TS packetincludes an SQH. In step S3, it is judged whether or not the input of TSpacket ended.

If the input TS packet includes an SQH, it is judged whether or not thestarting picture of a GOP in the video access unit, to which the SQHbelongs, is P/I picture (step S4). If the starting picture is not P/Ipicture but I/P picture or I/I picture, entry information including apair of a notified PTS and a notified SPN is added to the Entry group inthe EP_map (step S5).

On the other hand, if the starting picture of the GOP is P/I picture, itis judged whether or not the status flag is set to indicate that the P/Ipicture is not present (step S6). If the status flag is set so, thevalue of the status flag is set to indicate that the P/I picture ispresent but the EP_map does not specify the P/I picture (step S7), andthe control returns to the loop process composed of steps S2-S3. Thiscompletes the description of the procedures in which the EP_mapgenerating unit 5 generates the EP_map.

FIG. 9 shows the EP_map generated for the AVClip shown in FIG. 2. Thefirst row in the drawing shows the field structure of the target videostream; the second row shows the time axis of the AVClip; the third rowshows the EP_map for the AVClip; and the fourth row shows a sequence ofTS packets constituting the AVClip.

Each piece of entry information in the EP_map shown in the third rowincludes PTSs and SPNs of I/I pictures or I/P pictures, but does notinclude PTSs and SPNs of P/I pictures. The status flag is set to “1”.

When an AVClip is recorded in the recording medium 200 together with theEP_map structured as described above, the playback apparatus 300accesses only I/I pictures and I/P pictures whose PTSs and SPNs areincluded in the EP_map. FIG. 10 shows the playback process performed bythe playback apparatus 300 in which the EP_map is referred to. As shownin the drawing, the playback apparatus 300 performs the double-speedplayback by referring to the I/I pictures and I/P pictures. Accordingly,there is no omitting a first field during the playback.

As described above, the present embodiment removes the unstable factorfor the quality that the resolution changes between the full and halfdegrees depending on the access position, in so far as the playbackapparatus executes random accesses based on the entry map recorded onthe recording medium. This makes it possible to develop applicationproducts that handle VC-1 video streams, and to circulate theapplication products in the market. The home electric appliance industrywould gain great advantage effects from this.

Embodiment 2

In Embodiment 1, when the starting picture of a GOP is a P/I picture,the entry information on the picture is not generated. In the presentembodiment, the entry information on the P/I picture is generated. Inaddition, to cause the playback apparatus 300 to recognize the generatedentry information to be a P/I picture, the entry information is providedwith a type flag. FIG. 11 shows an internal structure of the recordingapparatus 100 in Embodiment 2. The recording apparatus 100 shown in FIG.11 differs from the recording apparatus 100 in Embodiment 1 in that eachentry is provided with a type flag when the entry group is generated,and that the EP_map generating unit 5 sets a stream type notified fromthe stream analyzing unit 2, in the type flag. In this way, as eachpiece of entry information in the entry group is provided with a typeflag, EP_map as shown in FIG. 12 is written onto the recording medium200.

FIG. 12A shows an EP_map that is provided with a type flag. As shown inFIG. 12A, each piece of entry information in the EP_map is provided witha type flag. FIG. 12B shows the meaning of the type flag. As shown inFIG. 12B, when the type flag is set to “0”, it indicates that thepicture data corresponding to the Entry information is an I/I picture oran I/P picture and is an official entry position. On the other hand,when the type flag is set to “1”, it indicates that the picture datacorresponding to the Entry information is a P/I picture and is apreliminary entry position.

FIG. 13 is a flowchart showing the procedures in which the EP_mapgenerating unit 5 generates the EP_map. When compared with FIG. 8, theflowchart of FIG. 13 does not include step S1, but includes steps S2-S4as in FIG. 8. The flowchart of FIG. 13 processes differently dependingon whether the result of the judgment in step S4 is Yes or No. When itis judged as No in step S4, the EP_map generating unit 5 sets the typeflag to “0”, and adds the entry information, which indicates a pair of anotified PTS and a notified SPN, to the Entry group in the EP_map (stepS10). When it is judged as Yes in step S4, the EP_map generating unit 5sets the type flag to “1”, and adds the entry information, whichindicates a pair of a notified PTS and a notified SPN, to the Entrygroup in the EP_map (step S11). This completes the description of theEP_map generation procedures in Embodiment 2.

FIG. 14 shows the EP_map generated for the AVClip shown in FIG. 2. Thefirst row in the drawing shows the field structure of the target videostream; the second row shows the time axis of the AVClip; the third rowshows the EP_map for the AVClip; and the fourth row shows a sequence ofTS packets constituting the AVClip.

Each piece of entry information in the EP_map shown in the third rowincludes PTSs and SPNs of I/I pictures, I/P pictures, or P/I pictures.The type flag of the entry information including PTSs and SPNs of I/Ipictures or I/P pictures is set to “0”; and the type flag of the entryinformation including PTSs and SPNs of P/I pictures is set to “1”.

Since the type flag of the entry information including PTSs and SPNs ofP/I pictures is set to “1”, the playback apparatus 300 can recognize, byreferring to the type flag, that the entry information indicates apreliminary entry position.

Up to now the recording apparatus 100 in Embodiment 1 has beendescribed. From now on, the playback apparatus 300 in Embodiment 2 willbe described. The playback apparatus 300 performs the jump-in playbackor double-speed playback by referring to the EP_map in which each pieceof entry information is provided with a type flag. In this playback, theplayback apparatus 300 performs processes in accordance with the typeflag in each piece of entry information, where the type flag indicateswhether the picture data corresponding to the piece of entry informationis (a) an I/I picture or an I/P picture or (b) a P/I picture. Morespecifically, when the entry position of a playback to be performed is aP/I picture, the playback apparatus 300 reads, into the decoder therein,a GOP that precedes, by two or three GOPs, the GOP to which the P/Ipicture belongs. This is done for the purpose of storing the picturedata referred to by the P/I picture, into the decoder. With thisstructure, the picture data referred to by the P/I picture is stored inthe decoder. This enables the jump-in playback or double-speed playbackto be performed without reducing the resolution.

On the other hand, when the entry position of a playback to be performedis an I/P picture, the playback apparatus 300 starts the playback fromthe picture data indicated by the entry information, as is the case withEmbodiment 1.

With the above-described structure in which depending on the setting inthe type flag, the playback apparatus 300 reads, into the decodertherein, a GOP that precedes, by two or three GOPs, the GOP to which theP/I picture belongs, it is possible to perform the jump-in playback ordouble-speed playback without reducing the resolution.

Embodiment 3

Embodiment 3 shows an example in which the EP_map described inEmbodiments 1 and 2 is structured in accordance with the BD-ROMstandard. When the EP_map is structured in accordance with the BD-ROMstandard, the EP_map is embedded in the Clip information. The Clipinformation is management information for managing AVClips, and isstored in a file with a file name that corresponds to a file name of anAVClip.

An AVClip is stored in a file with file name: “xxxxx.m2ts”. Here,“xxxxx” represents a five-digit value, and “m2ts” is an extension thatindicates “AVClip”. The Clip information is stored in a file with a filename that is composed of the five-digit value and extension “clpi”.

FIG. 15 shows the internal structure of the Clip information. Asindicated on the left-hand side of the drawing, the Clip informationincludes:

i) “ClipInfo( )” in which the attribute information of the AVClip file;

ii) “SequenceInfo( )” in which information regarding the ATC Sequenceand the STC Sequence is stored;

iii) “ProgramInfo( )” in which information regarding the ProgramSequence is stored; and

iv) “CharacteristicPointInfo(CPI( ))”.

The lead line cu1 in the drawing leads to a closeup of the structure ofa Program Sequence (Program Sequence (i)). As the lead line indicates,Program Info for Program Sequence (i) includes Ns(i) sets of Stream_PIDand Stream_Coding_Info (in FIG. 15, Stream_PID[i](0), Stream_Coding_Info(I,0), . . . Stream_PID[i](Ns(i)−1), Stream_Coding_Info (i,Ns(i)−1)).

The Stream_PID indicates a packet identifier for each elementary streamconstituting an AVClip. The Stream_Coding_Info indicates an encodingmethod for each elementary stream constituting the AVClip.

The lead line cu6 in the drawing leads to a closeup of the structure ofa Stream_Coding_Info. As the lead line indicates, Stream_Coding_Infoincludes Stream_Coding_Type that is information indicating the encodingmethod of the video stream. The Stream_Coding_Type indicates the type ofthe corresponding video stream that is one of VC-1, MPEG2-Video, andMPEG2-AVC. In the present embodiment, the Stream_Coding_Type has a roleof the status flag described in Embodiment 1.

When the Stream_Coding_Type indicates that the corresponding videostream is MPEG2-Video or MPEG2-AVC, it means that there is no P/Ipicture in the video stream, and therefore can have a role of the“status flag=0” shown in Embodiment 1.

When the Stream_Coding_Type indicates that the corresponding videostream is VC-1, it means that there may be a P/I picture in the videostream, and therefore can have a role of the “status flag=1” shown inEmbodiment 1.

As described above, the Stream_Coding_Type can be used as the statusflag described in Embodiment 1.

<CPI(EP_Map)>

Here, the CPI will be described. The lead line cu2 in the drawing leadsto a closeup of the structure of a CPI. As the lead line cu2 indicates,the CPI is composed of EP_map. The EP_map includes Ne pieces ofEP_map_for_one_stream_PIDs (EP_map_for_one_stream_PID(0) toEP_map_for_one_stream_PID (Ne−1)). The EP_map_for_one_stream_PID is theEP_map for each elementary stream constituting an AVClip. The EP_map isinformation that indicates a packet number (SPN_EP_start) that containsSequence_Start_Code of the starting picture of the video access unit inan elementary stream, in correspondence with the entry time(PTS_EP_start) of the starting picture of the video access unit.

The lead line cu3 in the drawing leads to a closeup of the internalstructure of an EP_map_for_one_stream_PID.

As shown in the drawing, the EP_map_for_one_stream_PID includes Ncpieces of EP_High (EP_High(0) to EP_High(Nc−1)) and Nf pieces of EP_Low(EP_Low(0) to EP_Low(Nf−1)). Here, the EP_High represents higher bits ofthe SPN_EP_start and the PTS_EP_start, and the EP_Low represents lowerbits of the SPN_EP_start and the PTS_EP_start.

The lead line cu4 in the drawing leads to a closeup of the internalstructure of an EP_High(i). As the lead line indicates, the EP_High(i)includes: “ref_to_EP_Low_id[i]” that is a reference value to EP_Low;“PTS_EP_High[i]” that indicates higher bits of the PTS; and“SPN_EP_High[i]” that indicates higher bits of the SPN. It should benoted here that “i” is an identifier for identifying a given EP_High.

The lead line cu5 in the drawing leads to a closeup of the structure ofan EP_Low. As the lead line indicates, the EP_Low includes:“is_angle_change_point(EP_Low_id)” that indicates whether or not thecorresponding video access unit can be decoded independently;“I_end_position_offset(EP_Low_id)” that indicates the size of the CodedI frame; “PTS_EP_Low(EP_Low_id)” that indicates lower bits of the PTS ofthe corresponding video access unit; and “SPN_EP_Low(EP_Low_id)” thatindicates lower bits of the SPN of the corresponding video access unit.It should be noted here that “Coded I frame” is the starting picture ofthe video access unit. The “Coded I frame” includes not only the I/Ipicture whose first field and second field are both the intra framecoding format, but also the I/P picture whose first field is the Intraformat and second field is the Predictive format. However, the “Coded Iframe” does not include the P/I picture whose first field is thePredictive format and second field is the Intra format. It should benoted here that the “EP_Low_id” is an identifier for identifying a givenEP_Low.

The above-described data structure of the EP_map is based on therecitation in the above-introduced Document or the like, and will not bedetailed any further in the present Description.

FIG. F16 shows the setting in the EP_map for the video stream. The firstrow indicates a plurality of pictures arranged in the display order. Thesecond row indicates the time axis for the pictures. The fourthindicates a TS packet sequence on the BD-ROM. The third row indicatesthe setting in the EP_map.

It is presumed here that in the time axis in the second row, P/Ipictures, I/I pictures, and I/P pictures are present in a period fromtime point t1 to time point t7. It is further presumed here that withinthe period from time point t1 to time point t7, a time period from t1 tot3, a time period from t3 to t5, and a time period from t5 to t7 areeach approximately one second. Then, in the EP_map for a video streamrepresenting a movie, t1, t3, and t3 among t1 to t7 are set as entrytimes (PTS_EP_start), and then the recording positions (SPN_EP_start)are set in correspondence with the entry times (PTS_EP_start).

FIG. 17 shows the PTS_EP_start and the SPN_EP_start of Entry Point #1 toEntry Point #5 shown in FIG. 16, by pairs of EP_Low and EP_High. TheEP_Lows are shown on the left-hand side of the drawing, and the EP_Highsare shown on the right-hand side.

Among EP_Low(0) to EP_Low(Nf−1) shown on the left-hand side of thedrawing, the PTS_EP_Lows of the EP_Low(i) to EP_Low(i+1) indicate lowerbits of t1, t3, t5, and t7, and among EP_Low(0) to EP_Low(Nf−1), theSPN_EP_Highs of the EP_Low(i) to EP_Low(i+1) indicate lower bits of n1,n3, n5, and n7.

On the right-hand side of FIG. 17, EP_High(0) to EP_High(Nc−1) in theEP_map are shown. Here, when t1, t3, t5, and t7 have common higher bitsand n1, n3, n5, and n7 have common higher bits, the common higher bitsare written in PTS_EP_High and SPN_EP_High. The ref_to_EP_LOW_idcorresponding to the EP_High is set to indicate the first EP_Low(EP_Low(i)) among EP_Lows corresponding to t1, t3, t5, t7, n1, n3, n5,and n7. With this arrangement, the higher bits that are commonly ownedby the PTS_EP_Start and the SPN_EP_Start are represented by the EP_High.

<Supplementary Notes>

The above description does not show all the embodiments of the presentinvention. The present invention can be achieved by the followingembodiments (A), (B), (C), (D), . . . . The invention defined in theclaims of the present application is expansion or generalization of theabove-described embodiments or modifications thereof. The level of theexpansion or generalization is based on the technical level in technicalfield of the present invention at the time the present application isfiled.

(A) The BD-ROM in Embodiment 3 can be produced by performing thefollowing processes in sequence.

First, a plot of how to play back the BD-ROM is planned (planningprocess), then video and audio materials are created by recording them(material creating process), and volume structure information is createdbased on the plot created in the planning process (scenario creatingprocess).

The volume structure information is information that shows, by abstractdescription, the format of the application layer of the optical disc.

After this, elementary streams are generated by encoding the video,audio, subtitle, and menu materials (material encoding process). Theelementary streams are then multiplexed (multiplexing process).

After the multiplexing, the multiplexed streams and the volume structureinformation are adapted to the application layer format of the BD-ROM sothat the general representation of the data to be recorded in the volumearea of the BD-ROM is generated (formatting process).

Here, the application layer format of the recording medium of thepresent invention is an instance of a class structure written in aprogramming language. And the BD-JObject, Clip information, PlayListinformation and the like can be created by writing instances of classstructures based on the sentence structure defined in the BD-ROMstandard or the BD-J standard. In doing this, table-format data can bedefined using the “for” sentence of the programming language. Also, suchdata that is necessary under certain conditions can be defined using the“if” sentence.

After the volume data is obtained by the adaptation process, it isconfirmed by playing back the volume data whether or not the results ofthe scenario creating process are correct (emulation process). In thisemulation process, it is preferable to simulate the buffer state of theBD-ROM player model.

Lastly, the press process is performed.

In this press process, the disc master is created by converting thevolume image into the physical data sequence, and performing the mastercutting using the physical data sequence. Further, the BD-ROM ismanufactured from the master created by the press apparatus. This BD-ROMmanufacturing includes processes of substrate forming, reflective layerforming, protection layer forming, bonding, and label printing.

With such processes, the recording medium (BD-ROM) for each embodimentis produced.

(B) The flowcharts shown in the above-described embodiments and theinformation processing of the functional components explained in theabove-described embodiments satisfy the requirements for the “programinvention” since the flowcharts and the information processing arerealized concretely using the hardware resources and are the creation ofa technical idea utilizing natural laws.

PRODUCTION OF PROGRAM OF PRESENT INVENTION

The program of the present invention can be produced as follows. First,the software developer writes, using a programming language, a sourceprogram that achieves each flowchart and functional component. In thiswriting, the software developer uses the class structure, variables,array variables, calls to external functions and soon, which conform tothe sentence structure of the programming language he/she uses.

More specifically, the process repeatedly performed in the flowchart iswritten using the “for” sentence or the like defined in the sentencestructure. The judgment process is written using the “if” sentence,“switch” sentence or the like defined in the sentence structure. Thecontrol on the hardware, such as the playback control on the decoder, orthe access control on the drive apparatus, is written as calling theexternal function supplied by the manufacturer of the hardware.

The written source program is sent to the compiler as files. Thecompiler translates the source program and generates an object program.

The translation performed by the compiler includes processes such as thesentence structure analysis, optimization, resource allocation, and codegeneration. In the sentence structure analysis, the characters andphrases, sentence structure, and meaning of the source program areanalyzed and the source program is converted into an intermediateprogram. In the optimization, the intermediate program is subjected tosuch processes as the basic block setting, control flow analysis, anddata flow analysis. In the resource allocation, to adapt to theinstruction sets of the target processor, the variables in theintermediate program are allocated to the register or memory of thetarget processor. In the code generation, each intermediate instructionin the intermediate program is converted into a program code, and anobject program is obtained.

The generated object program is composed of one or more program codesthat cause the computer to execute each step in the flowchart or eachprocedure of the functional components. There are various types ofprogram codes such as the native code of the processor, and Java™ bytecode. There are also various forms of realizing the steps of the programcodes. For example, when each step can be realized by using an externalfunction, the call statements for calling the external functions areused as the program codes. Program codes that realize one step maybelong to different object programs. In the RISC processor in which thetypes of instructions are limited, each step of flowcharts may berealized by combining arithmetic operation instructions, logicaloperation instructions, branch instructions and the like.

After the object program is generated, the programmer activates alinker. The linker allocates the memory spaces to the object programsand the related library programs, and links them together to generate aload module. The generated load module is based on the presumption thatit is read by the computer and causes the computer to execute theprocedures indicated in the flowcharts and the procedures of thefunctional components. The program of the present invention can beproduced in this way.

(C) The program of the present invention can be used as follows.

(i) Used as Embedded Program

When the program of the present invention is used as an embeddedprogram, the load module as the program is written into an instructionROM, together with the Basic Input/Output System (BIOS) program andvarious pieces of middleware (operation systems). The program of thepresent invention is used as the control program of the recordingapparatus as the instruction ROM is embedded in the control unit and isexecuted by the CPU.

(ii) Used as Application

When the recording apparatus is a hard-disk-embedded model, the BasicInput/Output System (BIOS) program is embedded in an instruction ROM,and various pieces of middleware (operation systems) are preinstalled inthe hard disk. Also, a boot ROM for activating the system from the harddisk is provided in the recording apparatus.

In this case, only the load module is supplied to the recordingapparatus via a transportable recording medium and/or a network, and isinstalled in the hard disk as one application. This enables therecording apparatus to perform the bootstrapping by the boot ROM toactivate an operation system, and then causes the CPU to execute theinstalled load module as one application so that the program of thepresent application can be used.

As described above, when the recording apparatus is a hard disk model,the program of the present invention can be used as one application.Accordingly, it is possible to transfer, lend, or supply, via a network,the program of the present invention separately.

(D) Production and Use of System LSI of Present Invention

The system LSI is obtained by implementing a bear chip on a high-densitysubstrate and packaging them. The system LSI is also obtained byimplementing a plurality of bear chips on a high-density substrate andpackaging them, so that the plurality of bear chips have an outerappearance of one LSI (such a system LSI is called a multi-chip module).

The system LSI has a QFP (Quad Flat Package) type and a PGA (Pin GridArray) type. In the QFP-type system LSI, pins are attached to the foursides of the package. In the PGA-type system LSI, a lot of pins areattached to the entire bottom.

These pins play roles of an input/output interface with the driveapparatus, an input interface with the remote controller, an interfacewith the television, an IEEE1394 interface, an interface with the PCIbus, and the like. Since the pins of the system LSI play such roles ofinterfaces, the system LSI, which is connected with various circuits ofthe drive apparatus and the recording apparatus through such pins, playsa role of the core of the recording apparatus.

The bear chips packaged in the system LSI are the instruction ROM, CPU,decoder LSI and the like that realize the functions of each componentelement included in the internal structure of each embodiment as shownin the drawings.

As described above in “Used as Embedded Program”, the load module as theprogram, the Basic Input/Output System (BIOS) program and various piecesof middleware (operation systems) are written into an instruction ROM.The major improvement of the embodiments is achieved by the load moduleas the program. It is therefore possible to produce a system LSI of thepresent invention by packaging the instruction ROM, in which the loadmodule as the program is stored, as the bear chip.

The details of the production procedures are as follows. First, acircuit diagram of a portion, which corresponds to the system LSI, iscreated based on the structure diagram shown in each embodiment.

As each constituent element is embodied, the buses connecting amongcircuit elements, ICs, and LSIs, and the peripheral circuits, andinterfaces with external devices are defined. Further, connection lines,power lines, grand lines, clock signals and the like are defined. Inthese definitions, the operation timings of each constituent element areadjusted by taking the specification of the LSI into account, and otheradjustments are made. For example, the band width necessary for eachconstituent element is guaranteed. In this way, the circuit diagram iscompleted.

After the circuit diagram is completed, the implementation designing isperformed. The implementation designing is a work of creating a boardlayout in which it is determined where on the board to place the parts(circuit elements, ICs, LSIs) that are written on the circuit diagramcreated in the circuit designing, and it is determined how to wire theconnection lines that are written on the circuit diagram.

Here, the implementation designing includes automatic placing andautomatic wiring.

When a CAD apparatus is used, the automatic placing can be achieved withuse of a dedicated algorithm called “centroid method”. In the automaticwiring, connection lines, which connect among pins of parts in thecircuit diagram, are defined using metal foils and vias. When a CADapparatus is used, the wiring process can be achieved using dedicatedalgorithms called “maze method” and “line-search method”.

After the implementation designing is performed and the layout on theboard is made, the implementation designing results are converted intoCAM data, and the CAM data is output to the facilities such as the NCmachine tool. The NC machine tool performs the SoC implementation or theSiP implementation based on the CAM data. The SoC (System on Chip)implementation is a technology for printing a plurality of circuits ontoa chip. The SiP (System in Package) implementation is a technology forpackaging a plurality of circuits by resin or the like. Through theseprocesses, a system LSI of the present invention can be produced basedon the internal structure of the recording apparatus described in eachembodiment above.

It should be noted here that although the term LSI is used here, it maybe called IC, LSI, super LSI, ultra LSI or the like, depending on thelevel of integration.

Further, part or all of the components of each recording apparatus maybe achieved as one chip. The integrated circuit is not limited to theSoC implementation or the SiP implementation, but may be achieved by adedicated circuit or a general purpose processor. It is also possible toachieve the integrated circuit by using the FPGA (Field ProgrammableGate Array) that can be re-programmed after it is manufactured, or areconfigurable processor that can reconfigure the connection andsettings of the circuit cells inside the LSI. Furthermore, a technologyfor an integrated circuit that replaces the LSI may appear in the nearfuture as the semiconductor technology improves or branches into anothertechnologies. In that case, the new technology may be incorporated intothe integration of the functional blocks constituting the presentinvention as described above. Such possible technologies includebiotechnology.

(E) In all the embodiments described above, the optical disc of thepresent invention is the BD-ROM. However, the optical disc may be anyrecording medium. For example, it may be an optical disc such asDVD-ROM, DVD-RAM, DVD-RW, DVD-R, DVD+RW, DVD+R, CD-R, and CD-RW, or amagneto-optical disk such as PD or MO.

(F) In all the embodiments described above, the video stream is theAVClip defined in the BD-ROM standard. However, the video stream may bethe VOB (Video Object) conforming to the DVD-Video standard or theDVD-Video Recording standard. The VOB is a program stream that isobtained by multiplexing video streams and audio streams, the programstream conforming to the ISO/IEC13818-1 standard. Also, the video streamin the AVClip may conform to the MPEG4 or WMV system. Further, the audiostream may conform to the Linear-PCM system, Dolby-AC3 system, MP3system, MPEG-AAC system, or dts system.

The description of each embodiment is based on MPEG4-AVC (also calledH.264 or JVT). However, the description may be made based on the MPEG2video stream. Also, the present invention can easily be applied to anyother image format (such as VC-1) in so far as the image in the formatcan be decoded separately.

INDUSTRIAL APPLICABILITY

The recording medium and recording apparatus of the present inventioncan be mass-produced based on their internal structures shown in theembodiments above. As such, the recording medium and recording apparatusof the present invention has the industrial applicability.

The invention claimed is:
 1. A non-transitory recording medium on whicha video stream and an entry map are recorded, wherein the entry mapincludes a plurality of pieces of entry information, each piece of entryinformation indicates an address of picture data, the entry map does notinclude entry information that indicates an address of picture datawhose first field is an inter frame predictive coding format and whosesecond field is an intra frame coding format, the entry map includesentry information that indicates an address of picture data whose firstfield is the intra frame coding format and whose second field is theinter frame predictive coding format, and the entry map recorded on thenon-transitory recording medium is referenced by a playback apparatusfor reading and playing back the picture data from the video streamrecorded on the non-transitory recoding medium.
 2. The non-transitoryrecording medium of claim 1 on which a status flag is further recorded,wherein the status flag indicates that the entry map does not includeentry information that indicates an address of picture data whose firstfield is the inter frame predictive coding format and whose second fieldis the intra frame coding format.
 3. The non-transitory recording mediumof claim 1 on which format information indicating an encoding method ofthe video stream is further recorded, wherein when the encoding methodof the video stream indicated by the format information is MPEG2-Videoor MPEG4-AVC, the entry map does not include entry information thatindicates an address of picture data whose first field is the interframe predictive coding format and whose second field is the intra framecoding format.
 4. A recording apparatus for writing a video stream andan entry map onto a non-transitory recording medium, the recordingapparatus comprising: a detecting unit operable to detect an address ofpicture data in the video stream; a generating unit operable to generateentry information in accordance with a result of the detection by thedetecting unit; and a writing unit operable to write an entry mapincluding the generated entry information onto the recording medium incorrespondence with the video stream, wherein if the detecting unitdetects an address of picture data whose first field is an intra framecoding format and whose second field is an inter frame predictive codingformat, the generating unit generates in the entry map, a piece of entryinformation indicating the address of picture data, and the generatingunit does not generate, in the entry map, a piece of entry informationindicating the address of picture data whose first field is the interframe predictive coding format and whose second field is the intra framecoding format.
 5. The recording apparatus of claim 4, wherein thewriting unit writes a status flag onto the recording medium, and thestatus flag indicates that the entry map does not include entryinformation that indicates an address of picture data whose first fieldis the inter frame predictive coding format and whose second field isthe intra frame coding format.
 6. The recording apparatus of claim 5,wherein if the video stream does not include a picture whose first fieldis the inter frame predictive coding format and whose second field isthe intra frame coding format, the writing unit causes the status flagto indicate that the video stream does not include the picture.
 7. Aprogram stored on a non-transitory recording medium for causing acomputer to perform a process of writing a video stream and an entry maponto a non-transitory recording medium, the program causing the computerto perform: detecting an address of picture data in the video stream;generating entry information in accordance with a result of saiddetecting; and writing an entry map including the generated entryinformation onto the recording medium in correspondence with the videostream, wherein if said detecting detects an address of picture datawhose first field is an intra frame coding format and whose second fieldis an inter frame predictive coding format, said generating generates,in the entry map, a piece of entry information indicating the address ofpicture data, and said generating does not generate, in the entry map, apiece of entry information indicating the address of picture data whosefirst field is the inter frame predictive coding format and whose secondfield is the intra frame coding format.
 8. A recording method forwriting a video stream and an entry map onto a non-transitory recordingmedium, the recording method comprising: detecting an address of picturedata in the video stream; generating entry information in accordancewith a result of said detecting; and writing an entry map including thegenerated entry information onto the recording medium in correspondencewith the video stream, wherein if said detecting detects an address ofpicture data whose first field is an intra frame coding format and whosesecond field is an inter frame predictive coding format, said generatinggenerates, in the entry map, a piece of entry information indicating theaddress of picture data, and said generating does not generate, in theentry map, a piece of entry information indicating the address ofpicture data whose first field is the inter frame predictive codingformat and whose second field is the intra frame coding format.
 9. Anon-transitory recording medium on which a video stream and an entry mapare recorded, wherein the video stream includes a plurality of pieces ofpicture data, the entry map includes a plurality of pieces of entryinformation the entry map includes entry information that indicates anaddress of picture data whose first field is an intra frame codingformat and whose second field is an inter frame predictive codingformat, the entry map does not include entry information that indicatesan address of picture data whose first field is the inter framepredictive coding format and whose second field is the intra framecoding format, and the entry map recorded on the non-transitoryrecording medium is referenced by a playback apparatus for reading andplaying back the picture data from the video stream recorded on thenon-transitory recoding medium.
 10. A playback apparatus for playingback a video stream recorded on a non-transitory recording medium, inaccordance with an entry map recorded on the recording medium, whereinthe entry map includes a plurality of pieces of entry information, eachpiece of entry information indicates an address of picture data, theentry map includes entry information that indicates an address ofpicture data whose first field is an intra frame coding format and whosesecond field is an inter frame predictive coding format, the entry mapdoes not include entry information that indicates an address of picturedata whose first field is the inter frame predictive coding format andwhose second field is the intra frame coding format, and the playbackapparatus reads picture data from the video stream recorded on therecording medium by referencing the entry map recorded on the recordingmedium, and plays back the picture data.
 11. A playback method forplaying back a video stream recorded on a non-transitory recordingmedium, in accordance with an entry map recorded on the recordingmedium, wherein the entry map includes a plurality of pieces of entryinformation, each piece of entry information indicates an address ofpicture data, the entry map includes entry information that indicates anaddress of picture data whose first field is an intra frame codingformat and whose second field is an inter frame predictive codingformat, the entry map does not include entry information that indicatesan address of picture data whose first field is the inter framepredictive coding format and whose second field is the intra framecoding format, and the playback method reads picture data from the videostream recorded on the recording medium by referencing the entry maprecorded on the recording medium, and plays back the picture data. 12.The non-transitory recording medium of claim 1, wherein the video streamis a VC-1 video stream.
 13. The recording apparatus of claim 4, whereinthe video stream is a VC-1 video stream.
 14. The program stored on thenon-transitory recording medium of claim 7, wherein the video stream isa VC-1 video stream.
 15. The recording method of claim 8, wherein thevideo stream is a VC-1 video stream.
 16. The non-transitory recordingmedium of claim 9, wherein the video stream is a VC-1 video stream. 17.The playback apparatus of claim 10, wherein the video stream is a VC-1video stream.
 18. The playback method of claim 11, wherein the videostream is a VC-1 video stream.